1. Field of the Invention
The present invention, in general, relates to a method and system of controlling an oil pump, and, more particularly, to a method and system of controlling an automotive electric oil pump.
2. Description of the Related Art
Vehicles are equipped with a plurality of oil pumps, and recently, an electric oil pump of which the operation is controlled based on the running state of a vehicle is increasingly used due to various requirements. Such oil pumps generally have an operation mechanism that pumps oil by rotating gears or vanes, thus causing differences in quality due to mechanical tolerances of the gears or the pump housing.
FIG. 1 is an exemplary graph showing the relationships between revolutions per minute (RPM) and generated pressure according to the quality of the electric oil pumps of the related art, showing the relationships between the RPM and the generated pressure of a highest-quality product with a highest quality, a lowest-quality product with a lowest quality, and a middle-quality product a middle quality. Referring to FIG. 1, when devices, such as a transmission, which use the electric oil pumps generate a desired pressure, the RPM of the electric oil pumps may vary due to the qualities thereof, and the difference may cause a difference in power consumption of the electric oil pumps and a difference in fuel efficiency of vehicles equipped with the electric oil pumps.
In the mass production of vehicles, it may be difficult to determine the difference in quality of the electric oil pumps mounted on the vehicle. Accordingly, in the design of a predetermined type of vehicles, the control of RPM of the electric oil pump may be designed to be based on a lowest-quality product to prevent issues with the vehicles equipped with a worst product. However, in this case, the fuel efficiency of vehicles equipped with a highest- or middle-quality electric oil pump decreases due to unnecessary power consumption. Further, since the quality of a predetermined type of electric oil pumps is about the same as the quality of the type of middle-quality product, electric oil pumps of over about 70˜80% mounted on a predetermined type of vehicles have quality at least beyond the middle-quality product. Therefore, FIG. 1 shows that when RPM of electric oil pumps is controlled based on some low-quality products, many vehicles equipped with electric oil pumps greater than the middle-quality product unnecessarily consume power and the fuel efficiency decreases. In other words, vehicles that are manufactured based on parameters of electric oil pumps that are known to underperform, fuel efficiency may decrease when an electric oil pump of higher quality is actually used within the vehicle.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.